[Openmp-dev] CMAKE_INSTALL_PREFIX vs -fopenmp and clang search library search path

[Chandler Carruth]

I already replied to the code review suggesting to enable it in the
projects/ tree. I don't understand why a bug report is necessary.

On Wed, May 13, 2015 at 10:55 AM Jack Howarth <
howarth.mailing.lists at gmail.com> wrote:

> On Wed, May 13, 2015 at 11:58 AM, Chandler Carruth <chandlerc at google.com>
> wrote:
> > I think that openmp should work much more like libc++ than like the
> > sanitizers. It has a reasonably stable API and even supports the libgomp
> > APIs and so it should be in the normal library tree just like libc++.
> >
>
> Chandler,
>        Is linux able to find the installed libc++ shared library when
> -DCMAKE_INSTALL_PREFIX=
> is used in the cmake build? On x86_64 darwin, the built libc++ shared
> library is installed
> in the lib subdirectory of the path from CMAKE_INSTALL_PREFIX.
> However, this isn't really
> exercised on darwin as the system libc++ is always used by default.
>
> > However, the CMake build of the openmp needs a lot of work. =/ It doesn't
> > match the patterns and structures of any of our other runtime libraries.
>
> Please do open bugzilla reports on those issues against the openmp cmake
> build.
>              Jack
>
> >
> > I think openmp needs to much more closely model its CMake build on
> libc++'s
> > before we do anything more. Currently I can't even reasonably include it
> in
> > my builds because it clobbers un-prefixed variable names and doesn't
> re-use
> > any of the LLVM CMake logic.
> >
> > Also, I'll point out that the CMake build completely and universally uses
> > the term 'iomp'. This trend really needs to reverse....
> >
> > On Wed, May 13, 2015 at 8:32 AM Jack Howarth
> > <howarth.mailing.lists at gmail.com> wrote:
> >>
> >>     I believe we have a gap in clang's library search path with the
> >> enabling of the openmp support via the proposed patch at...
> >>
> >>
> >>
> http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20150511/129075.html
> >>
> >> Currently, in tree cmake builds of the openmp library using
> >> -DCMAKE_INSTALL_PREFIX to install the llvm build in a buried
> >> subdirectory will place the libiomp5.dylib shared library in a
> >> directory outside of the library search path used by clang...
> >>
> >> % clang-3.7 -fopenmp -o omp_getEnvInfo omp_getEnvInfo.c -v
> >> clang version 3.7.0 (trunk)
> >> Target: x86_64-apple-darwin14.4.0
> >> Thread model: posix
> >>  "/sw/opt/llvm-3.7.0/bin/clang-3.7" -cc1 -triple
> >> x86_64-apple-macosx10.10.0 -emit-obj -mrelax-all -disable-free
> >> -disable-llvm-verifier -main-file-name omp_getEnvInfo.c
> >> -mrelocation-model pic -pic-level 2 -mthread-model posix
> >> -mdisable-fp-elim -masm-verbose -munwind-tables -target-cpu core2
> >> -target-linker-version 242 -v -dwarf-column-info
> >> -fno-unique-section-names -resource-dir
> >> /sw/opt/llvm-3.7.0/bin/../lib/clang/3.7.0 -fdebug-compilation-dir
> >> /Users/howarth/openmp_examples -ferror-limit 19 -fmessage-length 140
> >> -fopenmp -stack-protector 1 -mstackrealign -fblocks
> >> -fobjc-runtime=macosx-10.10.0 -fencode-extended-block-signature
> >> -fmax-type-align=16 -fdiagnostics-show-option -fcolor-diagnostics -o
> >> /var/folders/1l/n78sywl52lz6kkys6nv7mnph0000gp/T/omp_getEnvInfo-e20595.o
> >> -x c omp_getEnvInfo.c
> >> clang -cc1 version 3.7.0 based upon LLVM 3.7.0svn default target
> >> x86_64-apple-darwin14.4.0
> >> ignoring nonexistent directory "/usr/local/include"
> >> #include "..." search starts here:
> >> #include <...> search starts here:
> >>  /sw/opt/llvm-3.7.0/bin/../lib/clang/3.7.0/include
> >>  /usr/include
> >>  /System/Library/Frameworks (framework directory)
> >>  /Library/Frameworks (framework directory)
> >> End of search list.
> >>  "/sw/opt/llvm-3.7.0/bin/ld" -demangle -dynamic -arch x86_64
> >> -macosx_version_min 10.10.0 -o omp_getEnvInfo -liomp5
> >> /var/folders/1l/n78sywl52lz6kkys6nv7mnph0000gp/T/omp_getEnvInfo-e20595.o
> >> -lSystem
> >> ld: library not found for -liomp5
> >> clang-3.7: error: linker command failed with exit code 1 (use -v to
> >> see invocation)
> >>
> >> requiring an explicit path to passed to the compiler...
> >>
> >> % clang-3.7 -fopenmp -L/sw/opt/llvm-3.7.0/lib -o omp_getEnvInfo
> >> omp_getEnvInfo.c
> >> % otool -L ./omp_getEnvInfo
> >> ./omp_getEnvInfo:
> >> /sw/opt/llvm-3.7.0/lib/libiomp5.dylib (compatibility version 5.0.0,
> >> current version 5.0.0)
> >> /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
> >> version 1213.0.0)
> >>
> >> Currently, all the other shared libraries linked by the clang
> >> compilers (aside from libc++) are expected to be located in the
> >> clang/3.7.0/lib/darwin subdirectory (such as
> >> libclang_rt.asan_iossim_dynamic.dylib and
> >> libclang_rt.asan_osx_dynamic.dylib). Using CMAKE_INSTALL_PREFIX in the
> >> cmake build to bury the llvm installation has no impact on the usage
> >> of those two libraries with the -fsanitize flags but the current
> >> search library search path doesn't do the same for the libiomp5
> >> relocation in the same case.
> >>             Jack
> >> _______________________________________________
> >> Openmp-dev mailing list
> >> Openmp-dev at dcs-maillist2.engr.illinois.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/openmp-dev
>
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